BACKGROUND ART
From GB-B-1 565 966 ranitidine hydrochloride is known in a crystalline form that according to DE-C-3 139 134 is to be referred to an Form 1. It was not yet possible according to DE-C-3 139 134, however, to produce tablets with pure and highly crystalline ranitidine hydrochloride. That prior art provides for that purpose a new form of ranitidine hydrochloride that is said to be pure and highly crystalline and is referred to as Form 2. Form 2 can be obtained by recrystallisation of Form 1, it being possible to accelerate the recrystallisation process by adding seed crystals of Form 2.
According to DE-C-3 139 134, the X-ray diffraction spectrum of Form a is characterised inter alia by a strong band .theta.=10.degree. (4.40.ANG.) which Form 1 lacks according to Hohnjec et al. in Flory, Analytical Profiles of Drug Substances, Vol. 15, 1986, pages 549 to 550. The two forms can therefore be distinguished well from each other by means of radiography.
According to the prior art mentioned, therefore, at room temperature ranitidine hydrochloride exists as Form 2, whereas Form 1 is unstable, with the result that it changes into Form 2 in the presence of seed crystals of Form 2. It is therefore to be considered surprising that, according to the invention, tablets or capsules can be provided that are characterised by a powder mixture having a content of stable ranitidine hydrochloride Form 1 together with a carrier and/or diluent.